This invention relates in general to photographic apparatus. More specifically it relates to cameras that can expose, advance and process film selected from one of two separate supplies of self-developing film loaded in the camera.
In both conventional and self-developing photography, cameras that load two separate film supplies are known. For example, U.S. Pat. Nos. 2,616,342 to Thompson and 2,988,973 to Bohm et al. describe cameras that use a rotatable mirror to expose one of two rolls of conventional film. U.S. Pat. Nos. 3,608,456 to Hauser and 3,643,570 to Reid et al. describe a camera in which an image splitter simultaneously exposes both conventional roll film and self-developing film.
In recent years, self-developing films of the so called integral positive-negative type have become increasingly popular. These film units, in contrast to the earlier "peel apart" film, include all of the photosensitive and photoprocessing compositions in a self-contained laminar unit. U.S. Pat. Nos. 3,415,644; 3,651,746 and 3,779,770 disclose a form of self-contained film unit which is exposed from the same side on which the photographic product is viewed, as well as suitable holders for a stacked supply of these film units forming a cassette. Such film units have a transparent outer layer at only one surface and generally are exposed with actinic light reversed an odd number of times.
In contrast, U.S. Pat. Nos. 3,761,271 and 3,765,887 describe a self-contained film unit which is exposed and viewed from opposite sides; they also describe a container for a stack of the units. This type of film unit has two transparent outer surface layers. It commonly is exposed with light which has undergone an even number of reversals.
Since both of these films are presently on the market, it is desirable to have a camera that can accept either type of film. This capability is particularly important where the camera is used in different localities where only different ones of the two films are available.
A commonly assigned U.S. application Ser. No. 529,904 filed on Dec. 5, 1975 by William Plummer for "Photographic Apparatus" describes a camera that loads both types of self-contained film units and exposes whichever one the user selects. In one form, the camera employs a pivoted reflecting element that directs light to the "odd number" film in one position, and allows an uninterrupted, "straight-in" exposure of the "even-number" film in a second position. This camera employs a spread roll system which requires that both types of film units have the same thickness and employ identical processing. Further, the camera employs a separate pick mechanism for each set of film units. These and other characteristics restrict the widespread manufacture and use of the camera construction.
It is therefore an object of this invention to provide a dual film camera that reliably advances and processes self-developing film units from either of two film supplies with an integrated mechanical arrangement that minimizes the duplication of components for each film supply and is compact.
Another object of the invention is to provide selective film advance and processing mechanisms that are reliable and have a relatively low cost of manufacture.
Yet another object of the invention is to provide film advance and processing mechanisms for a dual film self-developing camera that are driven by a single motor and automatically advance and process a film unit from the film supply selected for exposure in response to that selection.